(1) Field of the Invention
The present invention relates to a solid-state imaging device which is used in a digital still camera and the like.
(2) Description of the Related Art
Rapid spread of digital still cameras and mobile phones having a built-in camera has permitted a remarkable expansion of the market size of solid-state imaging devices (see FIG. 1). Further, there are increasing demands for reductions in size and in thickness and for an increased number of functions of such digital still cameras and mobile phones having a built-in camera. For example, the reduction in thickness of digital still cameras or mobile phones having a built-in camera requires a reduction in thickness of camera modules of the cameras or mobile phones. The reduction in thickness of the camera modules in turn requires a reduction in the number of imaging lenses, a reduction of infrared cut filters, a reduction of antireflection filters, a reduction in size of packaging, and the like. At the same time, the solid-state imaging devices which are used in various imaging apparatuses used to perform monitoring or to be installed on vehicles, for example, are required to have multi-functions for capturing images at any time of day or night.
Patent Reference 1, Japanese Unexamined Patent Application Publication No. 2006-32886, is an prior art which discloses a solid-state imaging device in which an infrared cut filter and an antireflection filter are integrated on a cover glass of the solid-state imaging device for downsizing its packaging.
However, mere reductions of the number of imaging lenses, the infrared cut filters, or the antireflection filters lead to a degradation of characteristics of the camera module, and thus cannot be achieved easily. Furthermore, since an imaging device which can capture images at night has a different structure, it is extremely difficult to achieve capturing of images day and night with the same device. Moreover, even the technology described in the above mentioned Patent Reference 1 does not achieve a sufficient downsizing of the solid-state imaging device.